The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed. In the course of integrated circuit evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased.
As a part of the semiconductor fabrication, patterned photomasks or reticles (the terms photomasks and reticles are used interchangeably hereinafter) are used to pattern semiconductor features onto a wafer. A blank reticle (or a reticle blank) is used to create the patterned reticle. However, some blank reticles may contain defects, such as phase defects of an Extreme Ultraviolet (EUV) lithography mask. Without correction, these defects may cause problems in semiconductor fabrication and lead to device failures and/or low yields. As the geometry sizes for semiconductor features shrink and pattern density increases, it may be increasingly difficult to avoid these reticle defects.
Therefore, while existing methods of forming patterned reticles have been generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect.